What type of starter boat is good on both lakes and ocean?

We are thinking of buying a boat but don't know alot about it. What type of boat would be economy-priced and good for casual boating/ fishing on local lakes over weekends and short vacations to the Keys?

Rule of thumb for boating esp. a first boat , power or sail is to get the smallest boat safely suitable for the conditions you expect to use it in.
Look at your personal requirements as they will bear on boat size.
Things to consider....
Shelter... a cuddy cabin will give you a chance to get out of rain & sun , change clothes, possibly room for a small head or port-a -potty.
Maybe even limited galley space .
A relatively open boat can have a small cabin as well as a canvas top & side curtains.
Trailering..
Smaller boats are easier to tow & launch than bigger ones.
Hull type...
A deeper Vee hull is better for the sea & gives you more hull volume for things like a small cabin on a lake boat of same size.
Power.
Hours on engine if used boat.
Inboard engine w/ out drive or outboard ?
An ouboard saves on cockpit area & generally require less maintenance ,also wide HP range,
Yoy can get most if not all of these considerations on power or sail boats as small as 18'
Also consider the number of people you can expect to have aboard as well as the required safety gear.
The coast guard auxiliary would be the best source for boating safety, safety courses & info to help you make intelligent decision on what to buy
Be worth a few bucks to have a pro do a survey of the boat if you are looking for used.
Best of luck

Learn alot about them before you get in the ocean.
A center console or dual console bay boat is nice first boat.
Don't buy a cabin type unless you really need it, you loose so much space. A potty is nice too remember, you can't always jump in the water. Remember, Fla sun is tough, get a top for the boat.

Only you know how much the ratio of cruising to fishing you will do. Look at several styles, get in them, really think how you might pack for a day trip, how many will go and how long you would stay out. You will know when you hit the right one. More Questions & Answers ...